Space Exploration

1. Space Exploration Unit E Science InAction Pages 366-475

2. Section 1.0: 370-4o7 • Human understanding of both Earth and space has changed over time.

3. Early Views About the Cosmos • Objects in the sky have fascinated humans throughout time. • The explanations of how these celestial objects came to be are even more fascinating. • Early View Hyperlink

4. Ancient Views of the Cosmos • Myths, folklore and legends were used to explain what ancient people observed in the night sky. • First Nations people of the Pacific Northwest - believed the night sky was a pattern on a great blanket overhead, which was held up by a spinning 'world pole' resting on the chest of a woman named Stone Ribs. • Inuit in the high Arctic - used a mitt to determine when seal pups would be born, by holding the mitt at arm's length at the horizon.

6. Solstice • represents the shortest and longest periods of daylight • Winter solstice - shortest period of daylight (Northern hemisphere - Dec. 21) • Summer solstice - longest period of daylight (Northern hemisphere - June 21)

8. Solstice continued... • The Ancient Celts set up megaliths, in concentric circles, at Stonehenge to mark the winter and summer solstices. • Ancient African cultures set large rock pillars into patterns to predict the timing of the solstices as well.

9. Equinox • represents periods of equal day and night • Autumnal equinox - occurs in the fall (Northern hemisphere - Sept. 22) • Vernal equinox - occurs in the spring (Northern hemisphere - Mar. 21)

10. Equinox continued... • The Ancient Egyptians built many pyramids and other monuments to align with the seasonal position of certain stars. • The Mayans of Central America built an enormous cylinder shaped tower, at Chichen Itza, to celebrate the two equinoxes.

11. Equinox continued... • Aboriginal Peoples of SouthwesternAlberta used key rocks, which aligned with certain stars, in their medicine circles. • Ancient cultures tried to explain the motions of the stars and planets.

12. Two Models of the Planets • Geocentric - Aristotle's Model • Heliocentric - Copernicus' Model Assisted by Pythagoras and Euclid Confirmed by Galileo and Kepler

13. Two Models of the Planets continued... Geocentric and Heliocentric

14. Discovery Through Technology Section 1.2 Pages 377-383

15. Discovery Through Technology • The earliest astronomers used several tools to chart the position of objects in the sky and to predict where the sun, moon, and certain stars would move. • With the heavens serving as both timekeeper and navigational aid, such knowledge was of much more than scholarly interest

16. Early Telescope • Before 1609, when Galileo began using a brand new invention called the telescope, humankind's perception of the cosmos was limited to what could be seen with the naked eye. • It was natural to perceive Earth as the center of the universe (geocentric), with a transparent, starry sphere rotating around it.

17. Quadrant • Designed by Tycho Brahe • Tychonian quadrant was actually a very large brass quadrant, affixed to a wall. • Its radius measured almost two meters and was graduated in tens of seconds. • Sightings were taken along the quadrant through the small window in the opposing wall, to which Tycho points. • Allowed the observers to note the precise moment of observation.

18. Astrolabe • Instrument used to observe the stars and determine their position on the horizon. • The back had a moveable sighting arm and a scale for measuring altitude, while the front had a map of the heavens that helped to calculate the future position of objects. • Astronomers could predict when the sun and certain bright stars would rise or set on any given day. • Ipparch invented the astrolabe in the 2nd century B.C. • In the Middle Ages the astrolabe was the main instrument for navigation later to be replaced by the sextant. • At the beginning of the 20th century the prismatic astrolabe appeared, enabling the rays of a celestial body to be reflected onto a mercury surface to determine the point in time that it reached a certain height on the horizon.

19. Sextent • Tool for measuring the angular altitude of a star above the horizon, which was usually the sun. • Used for navigation. • Could be used to measure the height of a celestial body from aircraft, spacecraft or the ship's deck. • The main types are the sextant used for ships and the bubble sextant used only on aircraft.

20. Cross-staff • Made up of a straight staff, marked with graduated scales, with a closefitting, sliding crosspiece. • The navigator rested the staff on his cheekbone and lined up one end of the moving crosspiece with the horizon and the other end with the bottom of the pole star, or the sun at midday. • The position of the cross piece on the staff gave the reading of altitude.

21. Astronomical Unit (AU) • The astronomical unit (AU) is used for measuring 'local' distances in the solar system. • It is equal to the distance from the center of the Sun to the center of the Earth (approximately 149,599,000 kms). • 1 AU

22. Light Year • It is used for longer distances - to stars and galaxies. • The distance to our nearest star, Proxima Centauri is a little over 4 light years. • Speed of light approximately 300 000 km/s • A light yearis equal to the distance light travels in 1 year (approximately 9.5 trillion kms).

23. Parsec • A parsec is a basic unit of length for measuring distances to stars and galaxies • Equal to 206,265 times the distance from the earth to the sun, or 3.26 light-years. • The nearest star, Proxima Centauri is about 1.31 parsecs from the Earth.

24. Looking Into The Past • When you view an object in the sky you are seeing it as it was in the past. • Light from the Sun takes about 5 minutes to reach the Earth, whereas light from Pluto takes about 5 hours. • The farther away, the longer light takes to reach the Earth. • Light from the stars in the center of the universe takes about 25,000 years to reach the Earth. The Hubble telescope is capturing light from 12 billion years ago.

26. Distribution of Matter in Space Section 1.3 Pages 384-391

27. Stars • A star is a hot, glowing ball of gas (mainly hydrogen) that gives off light energy. • Very hot stars look blue, while cooler stars look red. • In the 1920's, EjnarHertzsprung and Henry Norris Russell compared the surface temperature of stars with its brightness (luminosity). • Stars fall into distinct groupings.

30. Birth of Stars

31. Birth of Stars

32. Life Cycle of a Star

33. Supernova • An enormous explosion that marks the death of a massive star. • Fusion has stopped and the star runs out of fuel. • Gravity causes the star to collapse upon its self. • The outer part of the star explodes with a shock wave.

34. Black Holes • A highly dense remnant of a star in which gravity is so strong that not even light from radiation going on inside the remnant can escape. • Event horizon – point at which light cannot escape. • Invisible to telescopes. • This shows how the path of a beam of light bends in the vicinity of a non-rotating black hole.

35. Star Groups • Constellations are the groupings of stars we see as patterns in the night sky. • There are 88 constellations and many are explained in Greek Mythology. • Asterisms are also groupings of stars but are not officially recognized as constellations.

36. Galaxies • A galaxy is a grouping of millions or billions of stars, gas and dust. • Held together by gravity. • The Milky Way Galaxy is the galaxy our solar system is a part of. • It is shaped like a flattened pinwheel, with arms spiralling out from the center.

37. Milky Way Galaxy

38. Types of Galaxies • Spiral – long curved arms radiating out from a bright central core – older to younger at the arms • Elliptical – football or egg – mostly old stars • Irregular – no notable shape – smaller size – mixture of young and old stars

39. Our Solar Neighbourhood Section 1.4 Pages 392-400

40. The Sun • The Sun emits charged particles in all directions. • This solar wind bombards the Earth at 400km/s, but the magnetic field of the Earth protects us.

41. Protoplanet hypothesis • 1. A cloud of gas & dust in space begin swirling • 2. Most of the matter (more than 90% of it) accumulates in the center - forming the Sun • 3. The remaining materials accumulate (forming planets) and circle the Sun

42. The Planets: Mercury • Closest planet to the Sun • Surface similar to our moon • No atmosphere • High temperature – 400oC sunny side • - 180oC dark side

43. The Planets: Venus • Similar in size, mass, and gravity to earth • High surface temperature – 450oC (melt lead) • 90 x atmospheric pressure to Earth • CO2cloud cover • Rotates opposite to other planets – east to west

44. The Planets: Earth • Only planet where water exists in solid, liquid, and gas • Only planet to support life • Atmosphere provides protection from the Sun • 70% surface covered in water • Active volcanism

45. The Planets: Mars • Red planet – orangish – caused by iron oxides on surface • Two polar ice caps (One of Co2 + H2O and one of CO2) • Extremely cold surface temperature • Varied surface topography • 2 moons

46. The Planets: Jupiter • Largest of all planets • Twice the mass of all other planets combined • Composed of mainly hydrogen and helium • Great Red Spot – atmospheric storm • Three thin rings • 28 moons

47. The Planets: Saturn • 19 moons • Second largest planet • 1000+ rings surround equator • Composed mostly of hydrogen and helium • High wind speeds over 1800 km/h due to fast rotation

48. The Planets: Uranus • Unusual axis of rotation – tilted toward the plane of its orbit –making it appear to roll its orbit • Composed mostly of hydrogen and helium • Methane in atmosphere gives it its blue colour • Large ring system • 17 moons

49. The Planets: Neptune • Composed mostly of hydrogen and helium, and methane • Methane in atmosphere gives it its blue colour • Little light reaches this planet • Fastest wind speed – 2500 km/h • Own ring system • 8 moons

50. The Planets: Pluto • Cold frozen ball of methane • Disqualified as a Planet due to its obit around the sun at 17.2o– more elliptical • Rotates east to west rather than west to east • Some astronomers believe it and Charon (moon) are comets that have been captured by the gravity of the sun • Originated from the Kuiper Belt